using UnityEngine;

public class RoadFenceGenerator : MonoBehaviour
{
    public GameObject waypointPrefab;
    public float spacing = 2f;
    public LayerMask roadLayer;
    public float raycastHeight = 10f;
    public float raycastDown = 20f;
    public int maxSteps = 1000;

    private void Start()
    {
        Vector3? start = FindStartPointOnRoad();
        if (!start.HasValue)
        {
            Debug.LogError("❌ No valid road surface found to start waypoint generation.");
            return;
        }

        Vector3 position = start.Value;
        Vector3 forward = transform.up; // because road is rotated -90 on X, forward is along global Y

        for (int i = 0; i < maxSteps; i++)
        {
            // Sample centerline at current position
            Vector3 rayOrigin = position + Vector3.up * raycastHeight;
            if (!Physics.Raycast(rayOrigin, Vector3.down, out RaycastHit hit, raycastDown, roadLayer))
                break;

            Vector3 waypointPosition = hit.point;
            Instantiate(waypointPrefab, waypointPosition, Quaternion.identity, transform);

            // Sample next point to determine forward direction
            Vector3 nextGuess = waypointPosition + forward * spacing;
            Vector3 nextRay = nextGuess + Vector3.up * raycastHeight;

            if (!Physics.Raycast(nextRay, Vector3.down, out RaycastHit nextHit, raycastDown, roadLayer))
                break;

            Vector3 nextPoint = nextHit.point;
            forward = (nextPoint - waypointPosition).normalized;

            position = waypointPosition + forward * spacing;
        }

        Debug.Log("✅ Waypoints placed along road center.");
    }
    public Transform startPoint;

    private Vector3? FindStartPointOnRoad()
    {
        if (startPoint == null)
        {
            Debug.LogError("❌ Please assign a startPoint Transform in the Inspector.");
            return null;
        }

        Vector3 rayOrigin = startPoint.position + Vector3.up * raycastHeight;

        if (Physics.Raycast(rayOrigin, Vector3.down, out RaycastHit hit, raycastDown, roadLayer))
        {
            Debug.DrawRay(rayOrigin, Vector3.down * raycastDown, Color.green, 2f);
            return hit.point;
        }

        Debug.LogError("❌ Raycast from startPoint missed the road.");
        return null;
    }
}